Scaffold hoist



W. C. FERRIS YsmxFFoLD HQgLST March 22, 1927.

Filed March 16. 1926 2 Shets-Sheet 1 March 22! C. FERRIS SCAFFOLD HOIST Filed March 16., 1926 2 Sheets-Sheet 2 ATTORNEY.

Patented' Mar. 22, 1927.

unirse stares PATET 'OFFICEn WALTON C. FERRIS, OF LINCOLN, NEBRASKA, ASSIGNOR TO NATONAL MANUFACTUR- ING COMPANY INC., OF LINCOLN, NEBRASKA, A CORPGRATION 0F NEBRASKA.

seAFFoLD Hois'r.

Application led March 16, 1926.

My present invention relates to scaffold hoists and is in the nature of improvement on the scaffold hoistas set forth in my prior Patent No. 1,57 7 ,617 granted March 2 3, 1926. The present invention has for its object the provision of a lever .device for elevating the platform, the lever device being` of the utmost simplicity both in construction and manipulation and possessing a degree of .safety not attained by even the lifting device set forth in my prior patent. It is a further object of my invention to proh vide such a design in the lever device that greater' flexibility may be obtained in the r degree of liftingof the platform since individual preferences and special circumstances very often detern'iine the best height to which the platform should be lifted during each individual operation.

Having invview these objects and others which will be mentioned in the following description, I will now refer to the drawings, in which- Figure 1 is a view in elevation of a single scaffold unit complete and with the overhead protection frame.

Figure 2 is a side view in end elevation of the same.

Figure 3 is a detail View in elevation of the cage assembly. f

Figure 4L is adetail view in elevation of a portion of the lifting lever in engagement and ready to be actuated.

Figure 5 is a detail View of the dog or pawl.

Figure 5^ is a detail view of the connector 28.

Figure is an illustration of the lowering tool.

Figure 7 is a view in elevation of a portion of the scaffold unit showing a modified form of the lifting lever and connections. c

Figure 8 is a view in elevation showing the modified form of carriage with dogs for engaging the pins. c

Figure 9 is a plan view of the lever 21 showing the bifurcated construction of the lever.

Figure 10 is a view in plan of the casting 14 and showing particularly the vertical opening through which the chain 1() passes.

As in the construction shown in my prior lSerial No. 95,077.

patent, I employ the pin-drop type of chain, and since this is fully described in my patent, l will but briefly refer to it in this connection. The chain consists of a plurality of rod-like links 10 connected end to end in such a way that the chain may be easily folded for storage and transportation and as easily unfolded for use. At spaced uniform intervals, preferably siX inches, the chain is provided with pins 11 which project from both sides thereof, these pins being either formed integral with the chain or driven through suitable apertures in the chain.

The putlog 12, the plank retainers 1S and in fact all parts of the platform are similar in construction to these parts as shown in my prior patent. At each corner of the platform is a casting 14, there being a pair of castings 111 for each end putlog 12. The castings 14 are each provided with a central aperture as shown in F 1.0 for receiving the chain 10 which slides freely therethrough. A pair of channel iron members 15 is secured in upright position to each casting 14 and at their upper extremities they receive between the members of the pair a dog cage as shown in Figure 3.

rldhe cage 1Gr is substantially rectangular in form vand is provided with a plurality of dogs 17. The number of these dogs may be varied as desired, but for obvious reasons an even number of dogs is preferable. 'lhey may be arranged so that two dogs of each pair are opposite each other and so that they simultaneous-ly fall in operative position against the two projecting portions of a pin 11 or they may be staggered so that the 'two dogs of cach pair will alternately and successively engage the projecting ends of the pin. These dogs are all spring pressed inwardly as shown in Figure 3. As shown in Figure 5 the dogs are provided with a channelled portion 17L and a notched portion 171 for positively engaging the pin 11. The springs 18 are coiled about the axes 19 on which the dogs 17 are pivoted, One en'd of each spring is anchored in the cage 17 as shown in Figure 3 and the other end passes through a` suitable aperture in the dog asehown in Figures 3 and 5. It will thus beiseen that the entire weight of the platform is sustained by the dogs engaging the pins 11. The inclination of the dogs with reference to the perpendicular as .shown in Figure 3 is important. Thethrujst on the dogs is very largely in a 'vertical direction so that there is little chance of slippage. The Weight of the platform acting through tne pinsll on the dogs tendsjto force their lower ends inwardly andinto'firme'r engagement with the pins, but if the dogs avere given a much greater inclination than that shown in Figure 3, tivo objections would develop. The dogs must engage the pins 11 but it `ivouldbe a sourc'eof annoyance if they were so inclined thatfthey would engage the f' link plate connecting the links ofthe chain.

Aside from this the thrust would bedirect'ed more in a horizontal direction `than 4is necessary. The dogs areroundedandVfshaped at their noses. 'flhe rounded-'nose of Athe dog causes `it to slide more readily over the surface of the chain support 10 and particle larly over any irregularities 'on the chain support. The V'shaped `end tends to `maine the engagement of the dog with 1the 'pins more secure and to align and Vto fl'fee'p aligned the pins. The tendency of any ehai'n support is to twist slightly -and this tendency is corrected lby the 1V-shapedfnoses of the dogs 17. The action ofthe lifting lever 21 also tends tto keep the pins 'in alignment because 'it straddles the chainiand because of the action of the fulcrum Seat 21.

The casting ldlalsohas integraltherewith an upstanding vportion spaced slightly `from the members 15. This upstanding portion comprises mainly a transverseweb havingla curved rib on eachrside thereof. Thecurv'atureof the rib 2O is shown in Figures 1 and Il. The rib -is designed to serve as a Ahoek for engaging the end of vthe liftingl lever. The rib may be lformed into a singlehookor into a plurality of hooks depending on the degree of liftdesired forleaeh stroke ofthe lever. ln my drawings and especially in Figure 1, l have shoivn ythe rib as iprovided with two *hook shaped portions Vwhich each provide a lift of three inches Whenusedv'vith the particular chain and ldog1construction which 1 have described. The lever itself is shown in Figure l. The lever lis forked to straddle the chain 110 and thel 'web portion of the casting 14C. At 21a the lever is provided ivith a socket fulcrum for engaging the pin 11 and at its outeriextremity itlhas a hook portion 21b `forengaging therib 20. A lever extension 22 may 'be firmly secured to the lever 21oritmaybeprovided toserve as a detachable accessory inthe formof a piecefof gaspipe or the like.

From the foregoing descriptionthe fmethod'of operation Amay be easily lunde'rstood. lThe Workman `on the platform simply places the lever 21 in engagement- With the upper hook of the rib 20, the ffulcrum being on the nearest pin 11. A s'lignt'pressure .pins 11. If it is then desired to give an additional lift to the platform, the inner end iofthe leveriis lifted lIto bring the hooked end 21b of the lever into engagement with the loiverhook of the/rib =as shown in 'ilfigure 1,1.and `the 'corner of the platform lmay thus befgiven a full flift from pinto pin of the chain With tivosimple strokes of the lever 21 and with the enpenditure `of `very little time'and effort. It is of course ,understood that @in the ordinary ipracti'c'e two Workmen are' provided With levers "Whichfthey actuate sinniltaneously'- on opposite sides of the platform"sothatthere will be noitiansiferse "tilting of the platform;

llhecage lihas integral therewith an outwardly and laterally extending ear` 23, 'and the ear 23 isprovided With-an elongated aperture 221. The upright 25 'is formed from ehannelled steel and is connected to `the ear 23 bylineans ofa detachable pin 26to permit folding of Vthe upright 25 against the meniber 15. The aperture 241 is elongated so as to permit insertion cfa-guardrail or cable or 4rope. rIhe pair -of uprights 25 is connected to theihorizontal overhead beam 27, a special form of connection being used 'for this purpose -asshovvn in Figures 1 and 2 and 15a. The connector 28 has the general shape of anphour glass anditpermitsjthe passage therethrough of the chain 10 While the platform is being elevated. The connector 2Sliasla pair-of spaced inner ears`29 and a pair of outer ears 30. The ears are secured "to and Within the channel upright 25 `Whilethe ears`29 are secured to the horizontal beam 27 and on the tvvosides thereof. @ne of the connecting pins Emay be .al rivet but the other should be a. bolt or other detachablelconneetion. As 'shown in Figure frL the connector 28 isformed in tivo partsa'nd 'when the Jbolt is removed one ofthe .parts may be swung on its connection to release the chain 10.` This is important in assembling and taking down the overhead protection `frame. n

1n Figure 7 is shown a modified form of the invention. In `this case there is a ffreely moving dog cage `-31 i'vhich supplements the cage 16. The cage 31 likethe cage llmay be provided With any desired number of dogs 117. At the bottomof the vcage '31 is a link 32 having a lever 33 pivotally connected at its IloWer'end. The'lever 33 is pivotally conneoted=`at its `outer end to the casting 34 which corresponds ina general 'Way tothe casting 14: shoWnin the other drawings. 1n

Cil

this modified form the lever s always in place since it is part of the apparatus and it cannot become lost. ln this case also the lever extension may be either permanently or detachably secured to the level'.

llfhen it is desired to lower the platform it is only necessary to spread a pair of the locking dogs 17 while holding the end of the lever to prevent too sudden a drop. ln the construction as described the drop can be only three inches when the second pair of locking dogs engages the pin 11. lhe lowering therefore must be gradual since the process must be repeated each three inches until the platform has been lowered the desired distance. While the dogs 17 are easily spread by the lingers, l have provided a special tool 35 as shown in Figure 6 for spreading the dogs. rllhis tool is a fork with a pair of beveled tines and it may be thrust into the dog cage at 36 straddling the chain l() so as to spread the dogs of a pair, whereupon the weight of the platform carries it downwardly to the next pin ll, the drop being checked by the use of the lever 2l. rlhe tool 35 is formed by casting or stamping, and preferably with the instructions as shown in Figure 6 so as to make it fool proof.7

Especial attention is called to .the form of the cage 16 and its relation to the dogs 17. 'lhe cage is in general rectangular in shape` but its upper lateral edges are beveled, this being the nal but important point in the safety of the scaffold hoist above described. The pair of dogs is wedged into engagement with the chain l0 and a pin l1. If one of these dogs should break or if its spring should become inoperative, the other dog` alone has an ample margin of safety to hold the weight of its portion of the platform, and it cannot slip because it is still wedged against the chain and the pin although the wedging angle of the dog has been changed. lf a pair of the dogs should become entirely inoperative, the worst that can happen is that the one corner of the platform will fall three inches, or to the point where the second pair of dogs engages a pin l1. Even in the almost impossible event that all of the dogs become crushed and their lower portions become broken, they will still be in wedging engagement with the chain. As long as only a fragment of one of the dogs of the upper pair remains, its jagged edges will be forced into direct engagement with the chain which is thus wedged against the inclined wall on the opposite edge of the cage. The inclined walls at the top of the cage have also a second but very important function in shedding chunks of mortar and particles of stone and thus preventing their entrance into the cage where they would tend to clog the dogs and corrode the mechanism.

The element of safety has been the primary consideration in the development of the present scaffold hoist. Aside from'the actual safety provided, there is thefidea of safety impressed on the workmen, and this is a psychological factor in the efliciency of the workmen. For example, when they look downward from a platform which is elevated by winding a cable on a drum, the workmen are apt to see only a very hard concrete sidewalk a hundred feet below. lWith the present scaffold hoist, however, they sce the chains reaching to the ground, and a veritable forest of pins confronts them, every one of which is designed for their safety. The fact that the hoisting mechanism is one of eXtreme simplicity 1s also a factor of great importance from both the mechanical and the psychological standpoint. Moreover, the simplicity of design leaves the platform clear for the workmen and the materials.

Having thus described my invention in such full, clear, and exact terms that its construction and operation will be readily un-v derstood by others skilled in the art to which it pertains, what I claim as new and desire to secure by Letters Patent of the United States is:

l. A scaffold hoist including a platform` and a support therefor, said support being adapted to be suspended from an Outrigger on a building structure, a hook projecting upwardly from said platform, means consisting of a rigid lever adapted to engage said support and said hook to raise said plat-v form on said support, and means on said platform for automatically engaging said support when the platform has been elevated a predetermined distance.

2. A scaffold hoist including a platform and a support therefor, said support being adapted to be suspended from an Outrigger on a building structure, a hooked member on said platform, means consisting of a rigid lever for engaging said support and said platform to elevate said platform on said support, and means on said platform fer engaging said hooked member when the platform has been elevated a predetermined distance, said means being adapted to prevent the lowering of said platform after the disengagement of said lever.

A scaffold hoist including a platform and a vertically disposed support therefor, said support being adapted to be suspended from a building structure in spaced relation to a wall thereof and being provided with a plurality of abutments at uniformly spaced intervals throughout its length, a plurality of dogs secured to said platform in vertical and spaced apart relation, each of said dogs being adapted to releasably engage one of said abutments to prevent downward movement of the platform, and means for lifting CFI llO

said platform such a distance `that the next dogof said plurality of dogs will engagethe Contiguoushigher `of said abutments.

4. A scaffold hoist including a platform and a support therefor, said support being adapted to be suspended in vertical posi tion from an outrigpger "on a buildingl strueture and being provided with a plurality' of abutments at uniformly spaced intervals throughout its length, a plurality of pairs ofdogs secured to said platform, each of said pairs of dogsbeinp; adapted to releasably one of said abutments to prevent downward movement of said platform, and mea ns for lifting said platform a distance such `that a second pair of said dogs will engage the nent higher of said abutments.

5. A scaffold hoist including a platform and support therefor,said support being adapted'to be suspended in vertical position from an outrigger on a building structure and being provided with a plurality of abutments uniformly spaced throughout its length, a standard on said platform, said standard being provided with means for guidingl said platform in its moven'ients lon said support, a plurality of pairs of dogs pivotally secured to said standard its upper extremity, each of said pairs of dogs being adapted to relleasablyfengage one of said abutments to prevent i downward *movement of said platform, and means for liftings'aid platform a distance such that a second pair of said dogs 'will "engage the next higher df said abu'tmerits.

o. A` scaffold hoistincluding a platform and a support tl1erefo`r,said support being adapted to ybe suspended Lin -vVertical `position from "anoutrigger on a building' str'utu're and being provided `with a plural-ity of abut ments at l uniformly lspaced intervals throughout the length thereof, a standard on said platform, a plurality of pairs of dogs k'on said'standa'rd at its upper extremity, each of said pairs of dogs being' adapted to sucoessirely engage said abutments on said ysupport to prevent downward movement of said platform, means for releasing said dogs from engagement with the abutment to permit'downward movement of the platform, and means for lifting` said platforma distance such that a eeeondfpair of said dogs will engage the next higher of said 'abutments,` said last named `mea-ns beingfadapted tobe used to retard the descent ofsaid platform when said'dogs arereleased fromenga'gement with the abutment.

ln testimony whereof I affix my signature.

VALTON C. FERRIS. 

